What Is Insertion Loss and Return Loss for Fiber Connectors?

What Is Insertion Loss?

In telecommunications, insertion loss refers to the loss of signal power, calculated as a ratio in dB (decibel), resulting from inserting a device in a transmission line or optical fiber. It can also be referred to as attenuation, which indicates how much the signal loss is by comparing the input power to the output power. A lower insertion loss value indicates a better insertion loss performance. For example, an insertion loss of 0.3dB is better than 0.5dB.

What Is Return Loss?

When a signal is transmitted through a transmission line, some signal power is always reflected or returned to the source due to discontinuities in the transmission line. The discontinuity can be a mismatch with the terminating load or with a device inserted in the line. Return loss refers to the loss of reflected signal power. Therefore, the higher the return loss is, the lower the amount of reflection will be. That is to say, the fiber connector will have better performance with a higher value of RL.